Power steering apparatus



POWER STEERING APPARATUS Filed Feb. 18, 1.933 2 Sheets-Sheet l y WILL/HM W. FULLER Oct. 4, 1938. w. w. FULLER POWER STEERING APPARATUS Filed Feb. 18, 1953 2 Sheets-Sheet 2 3mm: VV/LL/HM W FULLER Patented Oct. 4, 1938 UNITED STATES POWER STEERING APPARATUS William W. Fuller, Norfolk, Va., assignor to Hermoine Fuller, Norfolk, Va.

Application February 18, 1938, Serial No. 191,284

6 Claims.

This invention relates to an improvement in a power steering apparatus for vehicles in which mechanical impulses are utilized for steering the pilot wheels. This device is particularly adaptable for trucks and tractors where considerable manual effort must be applied. to the steering wheel in order to give the pilot wheels the desired turn. For example, when a car, truck or tractor is in a stationary position, the force necessary to turn the pilot wheels is many times greater than the force necessary to turn these same wheels should the vehicle be in motion. This increased resistance to turning is caused partially by the increased bond between the pilot wheels and the supporting surface while in a stationary position. It will also be noted that when in stationary position, if the wheels are only turned a very slight amount the resiliency within the tires will restore the wheels to the original position; consequently it is necessary to hold the steering wheel in the desired position against this resistance ofiered bythe tires. This resiliency in the tires plays a very important part in power steering mechanisms, because it is necessary to use mechanical impulses for moving the pilot wheels gradually in the desired direction. The smaller the impulses used, the more gradual and unnoticeable will be the change. Since very small impulses are used, there must be some means provided to follow up the wheel advancement made by these impulses to hold the wheels in the position placed. Otherwise the tires would return the wheels back to the original position, and the efiect of the power steering mechanism would only be to cause the front wheels to shimmy or vibrate. 1

It is, therefore, an object of this invention to provide a means for producing and utilizing mechanical impulses to turn the steering worm gear of an automobile with a follow-up means for holding the pilot wheels in the position placed by the maximum stroke of these impulses. Such an apparatus will allow very small impulses to be used and consequently the change will be smooth and unnoticeable. In other words, the

means for registering and retaining each impulse is provided in this apparatus;

It is another object of this invention to provide a power steering mechanism of the class described together with a suitable switch operable upon the turning of the steering wheels of the automobile to cause a motor to deliver the impulses which cause the pilot wheels to be moved in the desired direction. This switch is normally open when the wheels are directedstraight ahead.

When the driver fails to follow-up the turning movement of the steering wheel the switch will automatically open and cut oil? the power to the motor. I p

It is a further object of this invention to provide a rocker gear concentrically mounted on the steering shaft of an automobile, said rocker gear being driven by impulses from any suitable'source of power and means engageable with said rocker gear upon the turning of the steering wheel of the automobile to cause the pilot wheels of the car to be turned in the desired direction by the impulses. This rocker gear has teeth so con structed on theperiphery thereof that the engaging means will vnot stick when contact is made. The contact surface 'of the engaging means contacts the surface of the toothat a slight angle thus producing a tendency for the engaging means to slip off the tooth when the pressure on the steering wheelis released. This prevents any locking or sticking effect in the operation'of the pawls or engaging means; consequently the steering effect is directly dependent upon how much follow-up pull is applied to the steering wheel. I

Some of the objects of the invention having 4 been stated, other objects will appearas the description proceeds when taken in'connection with the accompanying drawings, in which Figure 1 is a plan view of the front portion of a chassis of an automobile showing my invention applied thereto;

Figure 2 is an elevation taken along the line 2-2 in Figure 1;

Figure 3 is an enlarged vertical sectional view with portions thereofbroken away, and taken along the line 3-3 in Figure 1;

Figure 4 is a transverse sectional view take along the line 4-4 in Figure 3;

Figure 5 is a sectional plan view taken along the line 5-5 in Figure 3; V

Figure 6 is a view taken along the line 6-6 in Figures 4 and 5;

Figure 7 is a sectional view taken along the line 11 in Figures 4 and 5;

Figure 8 is a schematic wiring diagram showing how the parts of the invention are wired electrically. I

Referring more specifically to the drawings, the numeral l denotes the chassisof a motor vehicle which has pivotally secured thereto as at H and i2 pilot wheels l3 and M, respectively. These pilot wheels are operated by suitable levers l and I6, which levers have the free ends thereof con- .nected to each other by'means of tie rod ll.

The

lever |6 has another arm |6a integral therewith to which is secured one end of a steering link 20, the other end of said link having a socket 2| thereon in which is mounted ball 22. This ball is disposed on the lower end of lever 23 which has its upper end fixedly secured to shaft 24.

The ends of shaft 24 are supported for oscillation by housing 25 which housing is'secured to the chassis ID of the automobile by any suitable means such as stud bolts .21. I v j V The housing 25'has a cover 28 secured thereto by any suitable means such as stud bolts 29, and; threadably secured in this housing is a cylindri-' cal steering column housing 30 "which projects j upwardly into the cabin of an automobile near the drivers seat. This housing has rotatably mountedtherein a steering column 3|, the lower end of said column having a spi-ra'lly disposed gear 32 fixedly secured thereon. This gear is engaged by a roller 33 which roller is rotatably' to the right and. thereby cause the pilot wheels I3 and M to turn in a clockwise manner.- "when the steering wheel 35 is turned in the oppo- Of course,

site direction, the pilot rwheels will -likewisevrb'e turned in the correspondingmanner. h

In order to provide a powersteeringmechanism in association with the conventional steering ap-- paratus just described, a ringgear 4B is mounteduponthe steering; column 3|. This gear is concentrically and freely mounted around the steering column 3| so'that it may rock'ineitherdirection. The inner periphery of ring gear40 has a plurality of'teeth 42'which teethare adapted to be engaged by pawls 43 or 44, depending upon the direction in which the steering columnis turned. Special attention is called to the bevel ends of the pawls 43 and 44 and also the bevel-teeth ,42.

These bevels are soconstructed that whenthe pawl 43 or the pawl 44' is rotatedintoengagement with the teeth 42, a slight angle will be present between these two surfaces, thereby creating a tendency for the end of the pawl to slide off the teeth when contact is madea'nd thus preventing the two surfaces from sticking togetheror'bind ing when the gear 40 is oscillated.

Thepawls 43 and 44 are constructed from one piece of material which in turn is pivctally. mounted as at 45' to the upper end of an arm 460.. This arm isintegral with hub 46 which is likewise lo'osely'mounted around steering column 3|. Extending'upwardly from the member upon which pawls 43 and 44i0C'Cul is'anarm 41' which is forked at its upper end. This'fork is adapted to accommodate a suitablepin 4B which pin projects laterally from upwardly'exteiiding arm 43 This arm 49 is integral with hub 56 which is fixedly secured around steering column 3|. -With the mechanism described, when the steering col- 1111111 3| is turned in a clockwise manner in Fig ure 4, the arm .49 will rotatein'the same manner and cause the pawls 43 and 44 to rotate in a clockwise manner about apivot point 45. When this is done, the pawl 43 will move up into engagement with the teeth 42 of gear wheel 40.

The upper portion'ofring gear 40 has integral rotated into engagement with teeth 42.

therewith a forked yoke 43a, in which is disposed an eccentrically mounted ring 55. This ring'55 is mounted around eccentric cam 56 which cam is fixedly secured around a motor shaft 5?. Suitable balls 58 are disposed between ring and cam 56. The motor shaft- 5'! extends from a motor 6E3, said motor being secured to cover 28 by means of bolts 29 and 6|. As the motor shaft 5lrotates, a rocking motion'will be'imparted to gear 4|] and its gear teeth 42. With the pawl 43 moved into engagement with the teeth 42 as heretofore described, it is evident that the clockwise rotation of the wheel 43 will also impart a clock wise rotation to the hub 46. The hub member 46 has another radiallyextending arm 63 integral therewith, said arm having a hollowed-out p01:

tion 64 near its outer end. Disposed in this ho'llowed-out" portion isan arm 65 which extends radially from hub 5. The arm 65 is normally held in a centered position in the l1ollowed-out portion 64 by means of springs 66-and t'hthese springs being disposed on the upper and,- the lower sides of the arm 65 and also within thehollowed-outportion 64. Y 46 is rotated in a clockwise manner, this rotation is imparted to the arm 65 and the hub 56 through the spring 66 which in turn will cause the steering 7 45 which, in turn, will cause the -paW1-44 to engage the teeth 42.

The rocking motion of the gear 4|] will impart.

a counter-clockwise motion to the pawls and member 46, as well as to the arms 63 and 35. The

motion from the arm 63 will be imparted to the arm 65 through the medium of spring 61 thereby clockwise manner due to the power delivered by the motor 60. 1 i v The pawls 43 and 44 are held in a centered PQ": sition relative to the upstanding arm- 46w by means of springs 69 and 7,.these springs being disposed upon opposed sides of a projecting lug 46b ofthe member 46. It is thus seen .thatwhen the driver fails to follow up themanual rotation of the steering wheel, the springs 69 and 10 will restore the pawls 43 and 44 to' a centered posi.

tion about the upstanding arm 46 which will cause pawls to become disengaged from the teeth 42 and 43. These springs also furnish an additional means for causing the pawls to be released from engagement with the gear teeth 42. 'The angularity of the teeth relative to the 'angulari'ty' of theends of the pawls '43 and 44 also play an important part in insuring that the pawls will not become stuck after once becoming engaged. It will be noted that the pawls 43 and 44 have integral therewith projecting portions 66a and llla'which are disposed on opposed sides of lug 46b. There is a slight clearance between this lug and portions 69a and 130. when the parts are in the normal-position as shown in Figure 4. If; for any reason, the springs 69 or 10' should become Therefore; when the hub 4 25 inoperative, the portions 6961. or 10a will engage the lug 4% upon the turning of the steering column and insure that the'pawls 43 or'44 will be Where the rotation'of the pawls is dependent upon the projections 69a and 10a. the apparatus is not quite so sensitive and the action of the pawls will be somewhat delayed; however, it will operate effec- 4O causing the shaft 3| to be-rotated in a counter- 7 tively. .As long as manual pressure or force is exerted upon the steering wheel 35 in one direction or in the other, one ofthe dogs 43 and 44 will beheld in aposition where the teeth 42 will engage the end thereof and for each: oscillation or stroke of the gear wheel 46, a corresponding movement will be delivered to the steering column 3I, to cause power from the motor to help steer the automobile. 4 g 7 As heretofore stated, these oscillations of the gear member 40 necessarily should be small to make the movement of the pilot wheels gradual and smooth. Where small oscillations are used, it is necessary to provide a follow-up mechanism for holding the advances of the pilot wheels made by these oscillations. There is a degree of elasticity in the automobile tires that will normally return the wheels to the original position, especially if the wheels have not been moved enough to break the bond between the wheels and the surface upon which they rest. Therefore, I have provided a follow-up mechanism which is operated simultaneously with the dogs 43 and 44 just described. This mechanism comprises a toothed ring 15 which is fixedly secured in a stationary positionto the cover 28 as at I6, (see Figure 5). Suitable dogs TI and "I8 are adapted to engage theseteeth when one of the pawls 43 or 44 is rotated into engagement with teeth 42. The pawls I? and I8 are pivotally secured as at 19 to downstanding arm 86 of the member 46. The dog I8 has a pair of pins 8I projecting therefrom between which projection 82 f pawl I7 is adapted to loosely fit,

The dogs TI and I8 movesubstantially at the same time, although they are held in a centered position about the downstanding arm 86 by any suitable means such as springs '84 and 85, said springs being disposed on opposed sides of lug 86 which projects from the downstanding leg 86. A suitable link 81 has its lower end connected to dog 11 and its upper endconnecting to hub 50 as at 88.

When the steering column 3| is turned in a clockwise manner, the dog 43 will "engage teeth 42 and at the same timethe dogs TI and I8 will be rotated in a'clockwise manner to cause the dog 18 to engage the teeth in gear 15'. Since these dogs move simultaneously it is seen that any advance made by the pawl 43, as a result of its contact with teeth 42, will beheld by the dog I8 which engages the stationary ring gear I5. Conversely, when the shaft 3| is turned in a counterclockwise manner, pawl 44 will engage teeth 42 and at the same time the pawl I! will engage the teeth in the stationary ring I to follow up the advances that are made in the opposite direction. Such a device furnishes a means for controlling the stepping-up, resulting from the impulses, and prevents any back-lash upon the steering column due'to the tendency of the pilot wheels to return to the original position, or due to the oscillation created by the cam 56. There are twice as many notches in ring I5 as in ring gear 4!]; therefore if the ring gear is only rotated one-half notch, the movement resulting from this advance will be held.

It is frequently desired to operate the steering device manually without aid of-power steering. When such is desired, it is only necessary to provide means for rigidly securing the arm 65 to the arm 63 so that no relative rotation can take place between the two members. When 'thisis done, there will be no possibility of an electrical contact being created.

This rigid connection between the arms 65 and 63 is established by means of a suitable forked member 90 (Figures 5 and '7). The forked end of member 90 fits over the portion 65a of arm 65 when the members 63 and 65 are connected together; This arm is shown in this position in Figure 7 at which time manual steering only can be accomplished. In Figure 5, the arm 90 is shown in a disconnected position, at which time power steering is accomplished.- The forked end of arm 96 is adaped to straddle the portion 65a and fit 'into' the cavity or hollowed-out portion 64 in the arm 63. The prongs of the forked member 96 are of such a thickness as to substantially fill up the space 64 not occupied by the portion 65a. of the arm 65, and when the forked member is placed in the position shown in Figure 7 the arms 63 and 65 must move together. The

1 arm 90 is fixed on the lower end of a rod 9| which rod is disposed Within thesteering column 3|. The upper portion of rod 9I hasa'suitable button 92 on the upper end thereof. Suitable notches 93 and 94m cut in the periphery of rod 9i and these notches are adapted to be engaged by a suitable spring 95 to hold the rod in the position placed.

With the spring 95 engaging notch 94 as shown in Figure 3, the forked member Wis pulled to a disengaged position as shownin Figure 5. When the notch 93 is' pushed downwardly into engagement with the spring 95, the forked member9fl will straddle the' portion 65a as shown in Figure 7, and in this position, any rotation which is impartedto the arm 63 will likewise impart the same amount of rotation to the arm 65. This will prevent the electrical contac'zts 6? or 98 from contacting the conductive surfaces 99 or I00; Since it is necessary that one of these contacts be made in order that the circuit to the motor 60 be established, it will be impo'ssiblefor power steering mechanism to be brought into play, with the forked member 90 inthe position shown in Figure 7. g i

'Leading from the contacts 91 and 6B is a conductive rod I02. This rod has a brush I63 on its outer lendwhichnormally presses against conductive ring 'I 04, said ring being secured to cover 28 by any suitable means such as bolts I65 and I06. Bolt I66 also actsas a conductive member to which one end of wire I0! is attached. 'This wire has its other end secured to motor 66 as at I68. Leading from the other side of motor 66 as .at IDS is another-wire IIIl,'-which' wire-is con-i nected to the positive terminal of battery I II. The battery I I I is grounded as at I I2 by wire I I4. Whenever the steering c'olumn3I isrotated to cause either dogs 43 or 44 to engage the teeth42, one of thecontacts 9'! or 98 will contactsurfaces 99 or I00 to cause the circuit to be completed, at which time'the current will'be allowed to fiow from the battery III through wire III} to motor 66, wire IIJ'I, conductive ring I64, brush I63, member I62, and to the'member 63 which acts as a ground. Likewise in this case, when the driver fails to follow-up the advance made by the steering mechanism; the springs66 and 61- will center the arm 65 relative to' the arm 63 at which time neither of the contacts ill or 98 will come into engagement with the surfaces 99 or I66. 'There-' fore, the motor 66 will stop. By using such a device, it is seen that the motor is only operated when it is necessary'to deliver the power, resulting in a very efficient steering mechanism.- It is, therefore seen thatI have provided a power steering mechanism which may be in-' In the drawings and'specification there has been set forth a preferred embodiment of the invention and although specific terms; are'employed they'are usedin a generic and descriptive.

sense only and not for the, purposes of limitation,

the scope of theinvention being set forthin the appended claims. V r

Iclaimr' 1 1. Power steering apparatus for motor vehicles comprising a steering column provided with a steering wheel, a housing surrounding a portion of said steering column intermediate itsiends, a ring gear having internal teeth andbeing mounted for oscillation on the steering column, a member loosely mounted on said column, a pawl member mounted for oscillation on said'member and h aving a pair of oppositely 'directed'pawls thereon adapted to engage said ring gear one at atime during a steering operation, said pawl v member having a slot therein, a member fixed on said steering column and having an arm provided with a pin for engaging said slot and impartingswinging movement to said pawl member to cause one of the pawls to engage'the teeth of said gear, said first member having a pair of spaced. contact points, said fixed-member having asecond arm provided with a pair of contacts for engaging one of the first pair of contacts when the steering column is rotated, an;electric motor having a circuit of which the spacedv contact pointsnform a part, a second ring gear fixed on the interior of said housing,'asecond pair of oppositely directed pawls mounted in'saidfirst member and engage able one at a time with said second ring gear, a link pivoted to said fixed member andto said lastnamed pawls for causing the last-named pawls to engage saidsecond gear when the first pawls engage the first gear to thereby hold the first pawls in position to prevent retrogrademove ment of the steering column. 7 W

2. Power steering apparatus for motor vehicles, comprising a steering column provided with a steering wheel, a housing surrounding a portion of said steering column intermediategits ends, a

ring gear having internal teethfand. being mounted for oscillation on the steering column, amember loosely mounted on said column, a pawl member mounted for oscillation on said member and having a pair of oppositely directed pawls thereon adapted to engage said'ring gear one at a time during a steering operation, said pawl member having a slottherein, a member fixed on said steering column and having an arm provided with a pin for engaging said slot and imparting swingingmovement to said pawl member to cause one of the pawls to engage the teeth of said gear, said first member having a pair of spaced contact points, said fixed'memb'er having a second arm provided with a pair of contactsfor engaging one of the first pair of contacts, when the steering column is rotated, an,,electric motor having a circuit in whichv the spaced contact points form a part; a'second ring gear fixed on the interior of saidhousinga second pairof oppositely directed pawls mounted in said first member and engageable one at a time with said second ring gear, a link pivoted tosaid fixed member and to said last-named pawls for causing the last-named 'pawlsatoengage said second gear whenthe first pawls engage the first gear to thereby hold the first pawls in position to prevent retrogrademovement .015 the steering column,

having a steering column, a casing surrounding a portion of the steering column intermediate its ends, an electric motor having a single circuit for energizing said motor. to run in one direction only,

a member mounted for oscillation by said motor, 7

means movable by rotation of the steering column for closing-the circuit to said motor to oscillate said member, and means also movable by rotation of the'steering column for connecting the steering column to said oscillating member to deliver force from the motor to the steering column. '2 e 4. Power steeringapparatus for motor vehicles having asteering column, acasing surrounding a portion of the steering column intermediate its ends, an electric motor having a single circuit for energizing said motor to run in one direction only; a, member mounted for oscillation by said motor, means movable by rotation of the steering column for closing the circuit to said motor to oscillate said member, means also movable by rotation of the steering column for connecting the steering column to said oscillating member to deliver force from the motor to the steering column, and additional means movable by turning movement of the steering column for preventing retrograde movement of the steering column as long as man-. ual' pressure isapplied to move the steering column in the selected direction. V

5. Power steering apparatus for motor vehicles having a steering column, a casing surrounding a portion of the steering columnv intermediate its ends, an electricmotor having a single circuit for energizingsaid motor to runin one direction only, a membermounted for'oscillation'by said motor, means movable by rotation of the steering col-f umn for closing thecircuit to said motorto oscillate said member, means also movablebyrrotation of the steering column for connectingthe steering column to said oscillating member'to' deliverforce from themotor to the steering col umn, and manuallyoperable means for prevente ing movement of the means movable by the steering column and also preventing energizationof themotor upon movement of the. steeringcolumn.

6. Power steering apparatus for motor vehicles having a steering column, a casing surrounding a portion of the steering column intermediate'its ends, an electric motor having a single circuit for f energizing said motor to run in one direction only, a member mounted for oscillation by said motor, means movable by rotation ofthe steering column for closing the circuit to saidmotor to WILLIAM ,W. FUILER- oscillate said member, means also movable by ro- 

